A Robust High On-Duty Buck Converter Achieving a Peak Effective On-Duty of 0.976 With EMI Suppression

초록

This article proposes a control method for buck converter used in a highly integrated system to ensure robust operation even when the converter operates with significantly high on-duty (D-ON). According to the D-ON, the proposed controller automatically changes the operation mode between fixed switching frequency (f(sw)) mode and fixed off-time (t(OFF))mode. In the fixed t(OFF) mode, the controller dithers the f(sw) to suppress the electromagnetic interference (EMI). The proposed converter achieves maximum effective D-ON of 0.976 at V-DD 5 1.8 V, V-O 5 1.7 V, and I-O 5 500 mA. This converter also reduces switching harmonics by 10 dB in the fixed t(OFF) mode. The chip was fabricated in 130-nmprocess.

키워드